Abstract
The irreversible field-induced phase transition between the antiferroelectric (P) and ferroelectric (Q) polymorphs of sodium niobate (NaNbO 3) ceramics constitutes a focal point in improving the material’s energy storage properties. The coexistence of P and Q phases can be verified by X-ray and electron diffraction methods, but its extent remains elusive. Two-dimensional solid-state nuclear magnetic resonance (NMR) spectroscopy allows the quantification of relative amounts of the coexisting polymorphs, but the analysis of ceramic sample pieces requires a trade-off between sufficient sensitivity (at higher magnetic fields) and separation of the overlapping P and Q signals (at lower magnetic fields). In this contribution, we apply thesatellite transition magic angle spinning (STMAS) pulse sequence in a quantitative analysis of the antiferroelectric−ferroelectric phase transition in NaNbO3 ceramics. Both field- and grain size-induced transitions are investigated and the coexistence of the Q and P phases after the application of an electric field is quantified to be approximately 50%:50%. No indication is found that the local structure of the field-induced Q polymorph differs fundamentally from that induced in small-sized grains. Furthermore, the
sensitivity and resolution of STMAS is compared to previously reported applications of the triple quantum magic angle spinning (3QMAS) sequence to the NaNbO3 system.
sensitivity and resolution of STMAS is compared to previously reported applications of the triple quantum magic angle spinning (3QMAS) sequence to the NaNbO3 system.
Original language | English |
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Pages (from-to) | 23852-23858 |
Journal | Journal of Physical Chemistry C |
Volume | 124 |
Issue number | 43 |
DOIs | |
Publication status | Published - 2020 |